The present invention relates to a device that provides samples to a measuring and testing apparatus. More particularly, the invention is directed to an automated device for providing samples to a measuring and testing apparatus.
Differential thermal analysis (DTA) generally refers to a calorimetric technique for measuring physical properties of a substance by exposing the substance to different temperature regimes. DTA can be employed to measure parameters associated with phase transitions, glass transitions, polymerization/depolymerization, crystallization, softening, sublimation, dehydration, decomposition, oxidation, cure kinetics and so forth. A differential scanning calorimeter (DSC) measures the temperature and heat flow associated with energy-emitting or energy-absorbing (exothermic and endothermic, respectively) material transitions. DSCs are widely used in academic, government and private facilities for research purposes, as well as for quality control and production purposes. Hereinafter, reference will be made to DSC, although it is to be understood to encompass DTA as well.
During DSC testing, the material being analyzed (xe2x80x9csamplexe2x80x9d) is heated or cooled according to a desired temperature profile. The results, such as differential temperature or heat flow, are measured and analyzed to understand the properties of the sample material. The basic theory of DSC analysis is well understood; the reader is referred to Reading, et al., U.S. Pat. No. 5,224,775 (the ""755 patent) and U.S. Pat. No. 3,456,490 (the ""490 patent) for details on the theory of operation of exemplary DSC systems. An improved DSC device is disclosed in U.S. patent application Ser. No. 09/767,903, entitled xe2x80x9cDifferential Scanning Calorimeterxe2x80x9d which was filed on Jan. 24, 2001, now U.S. Pat. No. 6,488,406, and which is herein incorporated by reference in its entirety.
There are also other well-known thermal analysis techniques, such as Pressure Differential Scanning Calorimetry (PDSC), Pressure Differential Thermal Analysis (PDTA), and Differential Photocalorimetry (DPC). The invention described hereafter may also be applied to instrumentation used for these techniques.
Typical DSC instrumentation includes the following basic components: a measurement module, a computer controller and associated software, and a results output device. The measurement module may include an interchangeable DSC cell, a cooling system, and a base cabinet. The DSC cell may also include a heated measurement chamber, which encloses a sensor assembly upon which the material to be analyzed is placed, and a furnace heater, which is used for heating the measurement chamber.
The cooling device may find application when temperature is being increased or decreased. Cooling devices used with DSC instrumentation include various types of heat exchangers, such as gas-cooled heat exchangers, liquid-cooled heat exchangers, and change-of-phase liquid-gas heat exchangers.
In the past, DSC testing was often a laborious, manual process, where a technician would have to load a sample pan with a sample, remove the cover(s) from the DSC cell, insert the loaded sample pan into the DSC measurement chamber, and replace the cover(s). After a test cycle was completed, the cover was removed from the DSC cell, the old sample pan was removed, the new sample pan was inserted, and so forth. If tests were to be conducted on multiple samples (such as might be the case for quality assurance testing in a large-scale manufacturing operation), the overall testing sequence would be very labor-intensive and time-consuming. Additionally, the manual nature of the process made it very likely that the testers would make errors, such as dropping or contaminating samples, misplacing samples, and so forth.
As a result, it was recognized that an apparatus for automatic sample retrieval and placement, an automatic sampler, would be beneficial. Accordingly, various automatic samplers have been developed. Some of these automatic samplers provide for a sample tray to be loaded with samples, which are retrieved and placed into the DSC cell.
However, current automatic samplers suffer significant disadvantages and drawbacks. For example, because some automatic samplers are robotic in nature, calibration becomes a significant issue. A number of factors may alter calibration: replacement of DSC cells; replacement of the sample tray; variations in sample tray size; autosampler component drift and wear; and so forth. Unfortunately, calibration of current automatic samplers is largely manual process. Not only is the calibration difficult and time-consuming, but the result is often suboptimal when performed by less-experienced personnel and/or when performed in a hurry. In fact, users of automatic samplers often avoid performing calibration because of these difficulties. Consequently, the DSC apparatus may begin to provide inaccurate measurements.
Additionally, some prior art automatic samplers perform calibration using a single sensing technique, e.g., an electrical sensor. However, a sensing technique can fail at times, such as when an electrical sensor is impaired by corrosion, oxidation, poor contact, and so forth. As a result, the calibration performed by such prior art automatic samplers can be inoperative or prone to errors.
Moreover, each of the various components in an automatic sampler (including calibration sensors) has its own tolerance and other variations. As a result, every automatic sampler that is produced can be slightly different from the others. Prior art automatic samplers have not taken this difference into account and, as a result, the calibration is suboptimal.
Some prior art autosamplers have employed robotic grippers for gripping sample pans to be placed in the DSC cell. However, prior art grippers have had a number of significant drawbacks. For example, the gripped sample pan is sometimes not centered in the grippers, resulting in difficulties in placement of the sample pan. Prior art grippers sometimes apply uneven pressure to the sample pan, resulting in crimped or damaged sample pans. Pans may stick or adhere to a gripper finger, resulting in misplacement of the sample pan in the DSC cell. Replacement of fingers in the prior art grippers can require removal of a number of parts, making gripper maintenance a difficult task. Finally, some prior art grippers used a sensor, e.g., an electrical sensor, for pan location. However, reliance on a single sensor can lead to pan location failures when this single sensor is not receiving a proper reading.
Accordingly, prior art automatic samplers have not been robust or flexible in terms of the types of equipment they can use. In some cases, only standard DSC cell types or standard pan types (open versus closed, metallic versus ceramic, etc.) can be used. In other cases, only pans with standard dimensions can be used. Sometimes, the sample tray can accept only a certain type of sample pan having certain dimensions. This greatly limits the flexibility of the automatic sampler.
The present invention is directed to an automatic sampler. The automatic sampler device includes a cell having a sample platform and a reference platform, a sample tray; and a sample arm. The sample tray has wells into which sample pans and reference pans are inserted. The geometry of the automatic sampler device permits the sample platform, the reference platform, and the wells in the sample tray to be accessed by the sample arm along a common arc.
According to another aspect, the automatic sampler device includes a sample tray with wells, a sample arm, and a gripper device. The gripper device has gripping fingers. The gripping fingers open or close in a manner that tends to center objects grasped by the gripper device.
According to another aspect, the automatic sampler device includes a sample tray with wells, a sample arm, and a gripper device. The sample arm has an optical sensor and an electrical sensor. The optical sensor and electrical sensor can be used to detect a pan grasped by the gripper device.
According to another aspect, the automatic sampler device includes a sample tray with wells, a sample arm, and a gripper device. The gripper advice is capable of grasping pans of different sizes.
According to another aspect, the automatic sampler device includes a sample tray with wells, a platen, a sample arm, a gripper device, and an optical sensor. The platen includes a reflective area used to calibrate the sample tray.
Accordingly, one object of the invention is to provide an automatic sampler that provides precise and repeatable measurements.
Another object of the invention is to provide an automatic sampler that is easy to use.
Another object of the invention is to provide an automatic sampler that allows the user to quickly and efficiently perform thermal analysis measurements on large numbers of samples.
Another object of the invention is to provide an automatic sampler with an improved calibration function that can be operated in a substantially automated fashion.
Another object of the invention is to provide an automatic sampler with sensors for providing a pan location capability.
Another object of the invention is to provide an automatic sampler having a platen for calibrating the automatic sampler.
Another object of the invention is to provide an automatic sampler whereby a sample platform, reference platform, and well can be accessed by a sample arm along a common arc.
These and other objects of the present invention are described in greater detail in the following description of the invention, the appended drawings, and the attached claims.
The present invention is directed to a gripper device. According to one aspect, the gripper device includes fingers with grasping ends. The gripper device includes a means to cause the grasping ends to open and close. When the means is engaged, the grasping ends open and close to define a circumference.
According to another aspect, the gripper device includes fingers, an upper flat member, and a lower flat member. The upper flat member and lower flat member have holes. The upper flat member and lower flat member are substantially parallel. The fingers have grasping ends. The fingers are inserted into the upper flat member and lower flat member. When the upper flat member is rotated relative to the lower flat member, the grasping ends of the fingers open and close.
According to another aspect, a gripper assembly has a gripper device with fingers and a rotating member. The fingers have grasping ends. The gripper assembly also has a motor and means for rotating the rotating member. The gripper device opens or closes the grasping ends in response to the rotation of the rotating member.
According to another aspect, a gripper finger has a top section, a middle section, and a bottom section. The gripper finger has a plurality of balls located above the grasping end of the gripper finger.
Accordingly, one object of the invention is to provide a gripper device that can be used to grasp objects of varying materials and dimensions.
Another object of the invention is to provide a gripper device that can be used reliably to repeatedly retrieve and release pans used in thermal analysis testing.
Another object of the invention is to provide a gripper device that tends to center pans grasped by the fingers of the gripper device.
Another object of the invention is to provide a gripper device that includes multiple fingers that open and close along a common circumference.
These and other objects of the present invention are described in greater detail in the following description of the invention, the appended drawings, and the attached claims.
The present invention is directed to a gripper device having sensors. According to one aspect, a sample arm has a gripper device with multiple fingers, an electrical sensor, and an optical sensor. The electrical sensor and optical sensor move with the sample arm.
According to another aspect, a sample arm has a gripper device with multiple fingers and a plurality of sensors. The sensors move with the sample arm. The sensors are capable of detecting an object or calibrating a coordinate.
According to another aspect, a sample arm has a gripper device with multiple fingers and a plurality of sensors. The sensors can be used to detect pans held by the gripper device. The sensors permit different kinds of pans to be grasped by the gripper device.
Accordingly, one object of the invention is to provide a gripper device with multiple sensors.
Accordingly, one object of the invention is to provide a gripper device with an improved pan detection capability.
Another object of the invention is to provide a gripper device that permits improved calibration.
Another object of the invention is to provide a gripper device that includes a redundant pan detection capability.
Another object of the invention is to provide a gripper device that can grasp different types of pans.
These and other objects of the present invention are described in greater detail in the following description of the invention, the appended drawings, and the attached claims.
The present invention is directed to a technique for performing a substantially automatic calibration of an automatic sampler device. According to an aspect, the automatic sampler device includes a cell with a sample platform and a reference platform; a sample arm; a sample tray, and a platen. The sample tray includes wells into which pans are inserted. The platen may include conductive and/or reflective areas for calibration. The sample arm has an electronic sensor and an optical sensor. The electrical sensor and the optical sensor are used to calibrate the positions of one or more of: the sample platform, the reference platform, and a well.
According to another aspect, autocalibration is optimized further by adjusting autocalibration results with a set of stored offset coefficients. The offset coefficients are generated by performing a manual calibration. The difference between the results of the manual calibration and an autocalibration are stored as offset coefficients. The offset coefficients can be applied to subsequent autocalibrations.
Accordingly, one object of the invention is to provide an autocalibration feature that with an improved accuracy.
Another object of the invention is to provide an autocalibration feature that can be substantially automated.
Another object of the invention is to provide an autocalibration feature that uses multiple sensors to gather calibration information.
Another object of the invention is to provide an autocalibration feature that accounts for tolerances and/or biases in the autocalibration apparatus.
These and other objects of the present invention are described in greater detail in the following description of the invention, the appended drawings, and the attached claims.
The invention relates to a sample tray to be used by an automatic sampler having a sample arm. According to an aspect, the sample tray includes wells that can be accessed by a sample arm along a common arc of rotation, without moving the sample arm in and out.
According to another aspect, the sample tray has several concentric rows of wells for holding sample pans and reference pans. Each row of wells lies along an inner circumference of the sample tray. The rows are placed so that when the sample tray is rotated, every well can be located on a common arc of rotation relative to a sample arm.
According to another aspect, a well in a sample tray is configured with a pan receiving area and finger receiving areas. Gripper fingers can be extended into the finger receiving areas to access pans of different sizes.
Accordingly, one object of the invention is to provide a sample tray that includes a large number of wells for testing multiple samples.
Another object of the invention is to provide a sample tray with wells that are oriented so that each well can be accessed by a sample arm along a common arc of rotation.
Another object of the invention is to provide a sample tray with wells that permit a variety of pan sizes to be used with an automatic sampler.
These and other objects of the present invention are described in greater detail in the following description of the invention, the appended drawings, and the attached claims.
The invention relates to a platen to be used with a sample tray of an automatic sampler. According to an aspect, the platen includes both electrically conductive and reflective areas that can be used to calibrate the sample tray. According to another aspect, calibration of the sample tray can be performed in all three dimensions.
Accordingly, an object of the invention is to provide a platen that can be used to calibrate a sample tray.
Another object of the invention is to provide a platen that includes electrically responsive areas and optically-responsive areas that can be used to calibrate a sample tray.
Another object of the invention is to provide a platen that includes responsive areas that can be used to calibrate a sample tray in all three dimensions.